JPH0711977B2 - Transistor type high frequency induction heating device - Google Patents

Description

TECHNICAL FIELD The present invention relates mainly to a transistor type high frequency induction heating device for heating a metal forging material by high frequency induction.

(Prior Art) A conventional high-frequency induction heating device for heating a forging material uses a thyristor element.

(Problems to be Solved by the Invention) A device using a thyristor element cannot obtain stable oscillation in a wide range of frequencies due to a commutation circuit and the like, and its power control must be performed by voltage control by phase control. It will be.

Therefore, large harmonics are generated in this phase control stage, and inductive interference occurs. In addition, the large electric noise generated at that time causes an obstacle to an electronic device that works with a weak electric power and causes a large electric pollution, which is a social problem.

Since the transistor can be turned on and off only by its base signal, stable oscillation can be obtained in a wide range of frequencies. Therefore, it can be controlled by the power control and does not require control of the power supply voltage, so that there is no electric pollution caused by it.

However, unlike a thyristor, a transistor cannot obtain a large amount of electric power, and therefore a large amount of electric power can be obtained only by parallel operation of a large number of elements.

In recent years, large-capacity devices have come to operate stably due to impedance balance, but since a large number of transistors operate in parallel, if one element is damaged, simply connect it in parallel. If they are arranged side by side, they will spread to other elements, which will increase the accident. Incorporating a stable element into each element in order to avoid such an accident is troublesome and economically disadvantageous.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the transistor type high frequency induction heating device in the present invention uses a plurality of transistors as a high frequency conversion element to improve power factor and prevent single excitation. A metallized polypropylene film capacitor with good high-frequency characteristics, which is a differentiating element, and a power balancer reactor are connected to each transistor, the ends of which are connected in parallel and led to an induction coil to form a transistor-type high-frequency induction heating device.

Furthermore, a plurality of transistors are used as a high frequency conversion element, and a metallized polypropylene film capacitor with good high frequency characteristics that is a differentiating element for improving power factor and preventing single excitation, and a power balancer reactor are connected to each transistor, and the terminals are connected. Transistor type high frequency induction heating device which is paralleled and leads to induction coil
It is also possible to connect a transistor inverter block unitized to about 15KW to a three-phase power source via a safety breaker (or safety fuse) and connect it to a high frequency output to form a transistor type high frequency induction heating device.

(Function) The capacitor and the balancer reactor are connected to the emitter collector of the transistor, and one end of the transistor is connected in parallel to the work coil, so that each transistor is directly connected in parallel, so that the additional sharing is made organic.

Therefore, a large capacity transistor-type induction heating device becomes possible by increasing the number of parallel connections. Furthermore, a transistor inverter block made by blocking a transistor type high frequency induction heating device is connected to a three-phase power source via a safety breaker (or safety fuse), and since it is connected to a high frequency output, if the safety element operates, Is detected, the oscillation is stopped instantaneously and automatically.

(Embodiment 1) The present invention will be described below according to an embodiment shown in the accompanying drawings.

In Fig. 1, transistors (1a) (1b) (1c) (1d) (1e) (1f) (1g) are placed between the DC circuits (5) and (6).
(1h) is provided for each transistor (1a) (1b) (1c)
(1d) (1e) (1f) (1g) (1h) to power balancer reactors (2a) (2b) (2c) (2d) and capacitors (3a) (3b) (for power factor improvement and single excitation prevention) 3c) (3d)
Connect each in series as shown in the figure, and each transistor (1a)
High frequency power can be extracted from (1b) (1c) (1d) (1e) (1f) (1g) (1h).

This high frequency power is applied to the work coil (4) to enable stable operation.

Furthermore, transistors (1a) (1b) (1c) (1d), power balancer reactors (2a) (2b) and differentiating element (3a)
By increasing the circuit of (3b) symmetrically, a large amount of power can be proportionally obtained.

That is, transistors (1a) (1b) (1c) (1d) (1e)
Connect capacitors (3a) (3b) (3c) (3d) and balancer reactors (2a) (2b) (2c) (2d) to the emitter collector of (1f) (1g) (1h), and connect one end of them in parallel. By connecting to the work coil (4), each transistor (1a) (1b) (1c) (1d) (1e) (1f) (1
g) It is the one that makes the addition sharing organic rather than connecting (1h) directly in parallel.

Therefore, a large capacity transistor-type induction heating device becomes possible by increasing the number of parallel connections.

(Example 2) A plurality of transistors (1a) as high frequency conversion elements
Using (1b) (1c) (1d) (1e) (1f) (1g) (1h),
A metallized polypropylene film capacitor (3a) (3b) (3c) (3d) and a power balancer reactor (2a) (2b) (2c) (2d) with good high frequency characteristics that are differentiating elements for improving power factor and preventing single excitation. Transistor inverter block (a) in which a transistor type high frequency induction heating device is connected to each transistor, the ends are connected in parallel, and is guided to an induction coil into a unit of about 15 KW.
This will be described below with reference to FIG.

The transistor inverter block (a) as described above is connected to the three-phase power source (10) via the safety breaker (11) (or safety fuse) and is connected to the high frequency output (12) to obtain a large amount of power. It is a thing.

When the safety element is activated, it detects it and instantaneously and automatically stops oscillation.

(Effect) As described above, the present invention uses a plurality of transistors as a high-frequency conversion element, and includes a metallized polypropylene film capacitor with good high-frequency characteristics, which is a differentiating element for improving power factor and preventing single excitation, and a power balancer reactor. A transistor-type high-frequency induction heating device that is connected to a transistor, has its ends connected in parallel, and guides it to an induction coil. By balancing the impedance, a plurality of transistors can be effectively operated in parallel to obtain large power. It is a thing.

Furthermore, the present invention uses a plurality of transistors as a high frequency conversion element, a metallized polypropylene film capacitor with good high frequency characteristics that is a differential element for power factor improvement and prevention of single excitation, and a power balancer reactor connected to each transistor, A safety circuit breaker (or safety fuse) is a transistor inverter block in which the terminals are connected in parallel and a transistor type high frequency induction heating device that is guided to an induction coil is unitized to about 15 KW.
Connected to a three-phase power supply via, high power can be easily obtained by connecting to a high frequency output, and if any one element such as a transistor is damaged, an element such as a safety breaker (or safety fuse) operates, By detecting it and automatically stopping the oscillation instantaneously, it has the effect of minimizing the spread of the accident.

[Brief description of drawings]

1 is a circuit diagram showing an example of a transistor type high frequency induction heating device, and FIG. 2 is a circuit diagram showing another example. (1) …… Transistor (2) …… Balancer reactor (3) …… Capacitor (4) …… Work coil (5) …… DC circuit (6) …… DC circuit (10) …… Three-phase power supply (11) ) …… Safety breaker (12) …… High frequency output (a) …… Transistor inverter block

Claims (2)

[Claims] 1. A metallized polypropylene film capacitor (3) having good high frequency characteristics, which is a differentiating element for improving power factor and preventing single excitation, using a plurality of transistors (1) as a high frequency converting element, and a power balancer reactor (2). ) Is connected to each transistor (1), the ends thereof are connected in parallel, and the induction coil is led to the transistor type high frequency induction heating device. 2. A metallized polypropylene film capacitor (3) having good high frequency characteristics, which is a differentiating element for improving power factor and preventing single excitation, using a plurality of transistors (1) as a high frequency converting element, and a power balancer reactor (3). ) Is connected to each transistor (1), its ends are connected in parallel, and a transistor-type high-frequency induction heating device that leads to an induction coil is unitized to about 15 KW. A transistor inverter block (a) is a safety breaker (11) (or A transistor type high frequency induction heating device, which is connected to a three-phase power supply (10) via a safety fuse and is connected to a high frequency output (12).